Advanced polymers for additive manufacturing: BP28 and new PVC formulations
Kai Parthy launches BP28, a backbone polymer to prepare custom feedstocks in the workshop. At the same time, a new European patent explores PVC-based formulations for material extrusion.
The sector of 3D printing of metals and ceramics is undergoing an important evolution on the materials front. Two recent developments aim to simplify feedstock preparation and expand the available options for material extrusion.
BP28: bringing feedstock formulation into the workshop
Kai Parthy, German developer known for Lay Filaments, proposes a new approach: a base polymer that allows preparing custom feedstocks without relying on commercial catalogs.
In Metal FFF and ceramic extrusion, the polymer is not the final material. It serves as a temporary structure: it carries the powder through the extruder, maintains the geometry of the printed part, and then is removed during debinding.
BP28 is positioned as a “backbone polymer”, a polymeric component designed for those who want to experiment with their own metal, ceramic, or carbide powders.
- Mixing of metal/ceramic powders with BP28 and water using a common mixer
- Oven drying at about 100°C
- Crushing of the dry material to obtain usable granulate
The proposed process is deliberately simple. The user mixes the powders with BP28 and water, dries the mixture at about 100°C, then crushes it to obtain a granulate.
The critical role of the feedstock
The binder formulation represents one of the main obstacles in the development of new material systems for Metal FFF and ceramics.
The Metal FFF process consists of three phases: printing the “verde” shape, debinding to remove the binder, sintering to consolidate the powder. The final result strongly depends on the feedstock: charge percentage, type of polymer, additives, extrusion behavior, and stability during debinding.
BP28 does not eliminate the need to know powders, temperatures, and thermal cycles. However, it aims to reduce a specific barrier: the preparation of the starting compound.
New formulations: the PVC patent for 3D printing
A European patent published in July 2026 explores the use of PVC-based blends for material extrusion, opening possibilities for materials with different characteristics.
Patent EP4772575A1 describes the use of polymeric materials composed of PVC resin, modifying polymers, and optionally inorganic fillers. The modifying polymer is a terpolymer of olefin, carbon monoxide, and an unsaturated carboxylic ester.
Material extrusion is one of the main categories of additive manufacturing according to the ISO 52900-2015 standard. The process deposits material under computer control based on a 3D digital model of the object to be produced.
The patent fits into the broader context of material extrusion, where formless materials (liquids, powders, granules) or form-neutral materials (filaments, wires) undergo chemical or physical processes such as melting, polymerization, or sintering.
Implications for the industry
These developments address concrete needs: greater flexibility in material selection and reduced dependence on specialized suppliers.
Parthy's approach with BP28 is aimed at those who want to develop proprietary materials or work with specific powders not available in standard catalogs. The technical barrier of binder formulation has so far limited experimentation to equipped laboratories or specialized companies.
The PVC patent, on the other hand, represents an exploration of new polymer families for material extrusion. PVC offers mechanical and chemical characteristics different from currently dominant polymers such as PLA, ABS, or nylon.
Both developments indicate a trend: the expansion of material options available for additive manufacturing, both through more accessible systems for feedstock preparation and through new polymer formulations.
The challenge remains in industrial validation. A backbone polymer or a new formulation must demonstrate reliability, repeatability, and compatibility with the thermal processes following printing.
article written with the help of artificial intelligence systems
Q&A
What is BP28 and what is it used for?
BP28 is a backbone polymer developed by Kai Parthy to prepare custom feedstocks for Metal FFF and ceramic extrusion. It is not a ready-to-use filament, but a base material that allows mixing metal, ceramic, or carbide powders with water, drying, and crushing to obtain a granulate.
What is the process for using BP28?
The process involves mixing the powders with BP28 and water using a common mixer, drying in an oven at about 100°C, and crushing the dry material to obtain a granulate suitable for extrusion. It is a deliberately simple method to bring feedstock formulation into the workshop.
What are the stages of the Metal FFF process?
Metal FFF consists of three stages: printing the 'green' shape, debinding to remove the polymer binder, and sintering to consolidate the metal powder. The final result strongly depends on the feedstock, including filler percentage, polymer type, and extrusion behavior.
What does the patent EP4772575A1 describe?
The European patent EP4772575A1, published in July 2026, describes the use of polymeric materials composed of PVC resin, modifying polymers (a terpolymer of olefin and carbon monoxide), and optionally inorganic fillers for material extrusion. It opens possibilities for materials with different characteristics.
What barrier does BP28 aim to reduce?
BP28 aims to reduce the barrier of preparing the starting compound for Metal FFF and ceramic extrusion. It does not eliminate the need to know about powders, temperatures, and thermal cycles, but simplifies the initial feedstock mixing, allowing experimentation with one's own powders without relying on commercial catalogs.
